Earth coring punch and drive apparatus therefor



March 14, 1967 N. D. BECKER 3,308,897

EARTH CORING PUNCH AND DRIVE APPARATUS THEREFOR Filed A ril 6, 1964 5Sheet5-Sheet l INVENTOR 2 NORMA/V 0. BECKER 1 p g g PATE T AGENT March14, 1967 N. D. BECKER 3,308,897

EARTH CURING PUNCH AND DRIVE APPARATUS THEREFOR Filed April 6, 1964 5Sheets-$heet 2 5O 46 52 WW LTYTHIT'U INVENTOR 5/ NORMA/V 0. BECKER PATENAGENT March 14, 1967 N. D. BECKER 3,308,897

EARTH CORING PUNCH AND DRIVE APPARATUS THEREFOR Filed April 6, 1964 3Shee ts -sheec 5 l I 1 I l I l l I I I l l I I I 65 3 INVENTOR Al. 0.BECKER QM 7W PATEN AGENT United States Patent F 3,308,897 EARTH CURINGPUNCH AND DRIVE APPARATUS THEREFOR Norman D. Becker, Calgary, Alberta,Canada, assignor to Becker Drilling (Alberta) Ltd Calgary, Alberta,Canada, a company of Canada Filed Apr. 6, 1964, Ser. No. 357,447 Claimspriority, application Canada, Nov. 6, H63,

883,474 5 Claims. (Cl. 175-405) This invention relates to earthexcavating tools, and specifically concerns a tubular earth coring punchfor penetrating the earth and its associated impact drive apparatus forpositioning and driving the punch, as well as apparatus for raising itfrom the ground.

Heretofore the excavation of holes for setting guard posts or piles inearth or fill which contains coarse gravel or boulders has been costlyand slow, requiring rock drills, explosives, and considerable manuallabour. While tubular earth corers are known which may be driven byimpact means for sampling soils free from stones, these tools areincapable of being driven into stony ground, particularly into rock fillmaterials used for highway roadbads. The use of rotary or churn drillsto sink bore holes in such rock fill, or in any stony ground, wears outbits at relatively high rates, and it is difficult to producesatisfactory holes by such tools. Consequently the placing of supportposts for highway guard rails and the like has been an expensiveoperation.

I have devised a simple yet robust tubular earth coring punch whichcarries an integral toothed annular shoe secured on the lower margin ofa strong tubular casing, and which may have any desired cross-sectionalconfiguration, whether round, oval, rectangular, or polygonal, the punchbeing carried by a suspension enabling it to be positioned accuratelyand to be driven into rock fill or even consolidated formations by highenergy percussion engine means to the depth required for setting eventhe largest posts or piles. The earth coring punch of my invention hasits internal cross-section so shaped as to retain within the casingsubstantially the entire volume of rock and earth which passes upwardthrough the shoe opening as it is driven down. Once the punch has beendriven to the desired depth, it is pulled up by the suspension means andraised clear of the hole, leaving a clean-walled borehole closelyconforming in cross-section to the form of the punch casing, whilesubstantially all of the hole contents are retained inside the punch asa core. In the digging of a succession of holes by use of the novel tooland method of my invention, the core volume held in the punch as aresult of a previous holesinking operation is discharged from a sideopening of the punch at a point above the ground level during itsdescent while the operation of punching the next hole proceeds.

Such coring punches when designed for unconsolidated ground preferablyhave a small taper in their side walls, which widen upwardly, so thatas'the shoe is driven down, the walls of the hole are progressivelycompacted by the sides of the punch. The resulting bore is smooth-walledand provides rigid support for a post, pillar, pile or column which maybe set and tamped in the hole thereafter, using the earth or rock whichhas been discharged from the side opening and which falls convenientlyclose to the hole.

' It is therefore my principal object in devising the earth perforatingtool and support apparatus, of my invention, to provide an impact-drivencoring punch carrying a toothed annular shoe fixed on its lower endhaving a cutting edge and transverse spaced teeth, the. punch being3,3fi'8,397 Patented Mar. 14, 1967 ice adapted to be positioned independing support relation from and disposed for impact drive by apercussion engine of high power for driving thereby into ground or fill,shattering and occluding stones or boulders encountered in its descent.It is my further and important object to provide a punch casing soshaped as to retain within the casing substantially the entire contentsof the hole made by the shoe while the tool is raised.

Essentially my invention consists in a transportable earth-perforatinghollow punch having any desired crosssection and any length suitable forthe depth of hole to be sunk, detachably carried suspended by its upperend from a high energy percussion engine, and disposed for impact drivethereby, the engine and punch being carried by an adjustable frameworkmounted in the carrying 'ehicle and being jointly adjustable in positionlaterally and vertically, the punch being also independently pivotableabout a horizontal axis adjacent its upper end and having its lower endfitted with an integral shoe of annular form carrying integral teethaligned with the axis of the punch and spaced about the periphery of theshoe. The cutting edge of the shoe lies substantially along the outermargin of the shoe, which thickens upwardly to provide a constrictedopening whose cross-sectional area is significantly less than thecross-section at the cutting edge. A series of rock-breaker chisel-liketeeth extend inwardly as well as below the cutting edge and project intothe opening of the shoe to shatter or otherwise displace rocks in orderthat the fragments will move up through the shoe.

Among the advantages to be derived from the use of the earth perforatingtool and apparatus hereinafter to be described are the ease ofaccurately positioning the cutting edge with respect to a desired holeposition, and the precision of adjustment of tool inclination to thevertical prior to the driving operation. A hole for placing utilitypoles may be sunk to a typical depth in the range from four to five feetin less than a minute in yielding ground or fine gravels, while intypical roadbed material or rock fill the time required may be as shortas two to three minutes. in contrast to these elapsed time inervals, thesinking of a hole in the shoulder of a highway by conventional methodsand tools may require up- Wards of one hour. A succession of holes mayeach be driven on the average more rapidly than it is possible to movethe carrying vehicle into position. There is no loss of time indisposing of the hole contents.

It is an important aspect of my invention that the work of sinking ahole by driving an annular shoe of the shape which I have found to bemost eilicient and as will be described hereinafter, is a small fractionof the amount of work required to sink a hole byconventional drillingtools. This saving apparently is due to the fact that the work ofdriving the relatively small cross-section of the cutting edge of theannular shoe to penetrate the undisturbed ground or rock is far lessthan the work required to grind or reduce to fragments the entire volumeof material which is to be removed. It has been found that the totalwork expended in sinking a square hole of crosssection area one squarefoot is considerably less than the work which would be required to drilla hole whose cross-sectional area is equal to the projected area of theshoe, which for the embodiment referred to was thirtyfive square inches.Economies in fuel consumption are therefore realized.

It is also an advantage of the present invention that holes may be sunkrapidly at substantial inclinations to the vertical, as for examplebeneath a curb or wall, to provide access to underground service linesand the like.

The foregoing and further advantages and features characterizing myinvention will become more directly apparent from a study of thefollowing description of its 3 preferred embodiments which are describedin conjunction with the accompanying drawings, wherein:

FIGURE 1 is a perspective view showing a punch coring tool according tothe invention as mounted on a carrying vehicle, suspended from apercussion drive engine;

FIGURE 2 is a side elevation view of the apparatus of FIGURE 1 showingthe tool in raised position in relation to tilt ranges, the supportcolumns being partly cut away for clarity;

FIGURE 3 shows a punch coring tool in vertical axial cross-section, asdriven into the ground, excluding drive or support apparatus forclarity;

FIGURE 4 shows the punch shoe in bottom plan View; 1 FIGURE 5 is anenlarged scale cross-section of the shoe of FIGURE 4 taken on line S'5thereof;

FIGURE 6 isa vertical diametral sectional view through the upper end ofthe punch coring tool and the coupling by which it is adjustablysupported from the drive engine;

FIGURE 7 shows an alternative form of punch corer having interior andexterior cross-sectional areas of its shank of opposite taper;

Referring to the drawings, FIGURES 1 and 2, a transportable coring punchaccording to the invention comprises a wheeled, self-propelled carryingvehicle generally designated 10, having horizontal frame beams 11carrying a punch tool assembly generally designated 12, together withassociated operating elements and conventional engine, transmission, andsteering means, for powering the apparatus and moving it about from onelocation to, another. An elongate punch-suspending framework comprisingspaced upright side columns 13 and transverse upper bracing element 15is pivotably supported by its lower ends upon pivot axles 16. The latterare short stub shafts projecting outwardly from the side columns and arejournalled in bearings 17 fixed on the rearwardlyextending ends of thevehicle frame beams 11.

As may best be understood by reference to FIGURE 2 the inclination ofthe framework about a pivot axis in bearings-17 may be adjusted byactuation of a linear hydraulic motor 18 whose rod extension 19 ispivotably connected' by one end in the forward part of the vehicle framemember and whose cylinder extension 20 is pivotably connected by aremote end'with a column. It will be seen that the center line of thesupport framework may be varied between a forward position indicatedby-dashed line 21 and a rearward position indicated by dashed line 22,affording a range of fore-and-aft angular positions of at least twentydegrees are. 7

The adjustably positionable upright framework supports a verticallymovable open-ended box-like slide structure designated 14, comprisingfront and back vertical cover panels 23, and integral vertical joiningend members 24. The latter aresuspended from upwardly extending tensionstruts 25 slidably received within the side columns 13, which preferablyare of channel form. The upper ends of tension struts 25 are in turncarried by the upper ends of movable piston rods 26. Each of the pair ofcylinders 27 from which piston rods 26 are reciprocably extensible hasits base 28 supported in a bracket 29 secured in the lower end of arespective side column. The tension members 25 accordingly may becontrollably reciprocated by operating the pistons by means ofconventional valve means under suitable applied fluid pressure, to causethe entire box slide to move guidedly up and down. 'Cover panels 23closely fit in freely sliding relation against the channel flanges ofthe side columns which serve as guides or ways to restrain the slide inthe fore-and-aft direction while the tension struts provide restraint inthe lateral motion.

The fluid-operated linear motors which raise and lower the box slide arepreferably of substantial lifting capacity and of long stroke, forexample in excess of six feet in a machine designed to set utilitypoles.

The upper and lower margins of cover panels 23 are secured as bywelding.

thickened outwardly to provide upper and lower pairs of flange ways 30and 31 projecting to the front and to the rear from the top and bottommargins of the box slide. A percussion engine generally designated 32having a casing 33 is carried within the box slide which requires tohave inner dimensions sufiiciently large to permit lateral movement ofthe casing within it. The engine casing carries upper and lower pairs ofprojecting bracket memhers 34 and 35 fixed on the forward and rearwardsides which engage flanged ways 30 and 31 of the box slide and which arelaterally movable to permit positioning of the engine. Such positioningmay be effected by controllably energizing a further hydraulic motorcomprising cylinder 36 supported by an end on the box slide and havingits piston rod secured by an end to the engine casing, suitableoperating means'being provided (not shown) to actuate the motor formovement of the engine in either direction.

The'percussion engine 32 may be of any form, provided that it haveadequate energy output, and may comprise an airor steam-operated hammeror an internal combustion hammer suitable for a mobile punch. Suchhammers may desirably be conventional two-cycle diesel free-pistonengines and such type is generally illustrated in the drawing. Theenergy delivered per blow to the punch tool next to be described shouldbe upwards of 3,000 foot pounds, and preferably should be as much as8,000 foot pounds or more for punch corers designed to produce a hole ofone square foot cross-section in coarse gravels and rock fill.

Referring additionally to FIGURE 3, the earth coring punch generallydesignated 37 comprises an elongate steel'casing 38 illustrated ashaving a square cross-section. Each sidewall is'of quadrilateral shape,widening upwardly and having its longer side edges 39, 40 inclinedequally to a center line at a small angle, for example in the range 0 toabout 7 degrees. 'The four side walls are integrally joined together attheir meeting edges, forming a tube of truncated pyramidal form havingbottom edges 41 disposed in the plane of the lower opening 42 and theirupper edges 43 integrally joined with a closing end wall 44. The latteris parallel with the plane of lower opening 42 and at right angles to alongitudinal axis. of the tube. The lower margins 41 are integrallyjoined with an open, annular shoe generally designated t5 having adepending cutting edge 46 disposed in a plane spaced below and parallelwith the plane of opening 42.

Turning now to FIGURE 4 and FIGURE 5 it will be seen that the shoethickens upwardly in cross-section, and that the dimensions of theaperture 47 which is bounded by the cutting edge 46 exceed thedimensions of upper aperture 42. The upper face 48 of the shoe projectsinwardly beyond the inner surfaces of the casing to provide a ledge orshelf 49, upon which the casing is rigidly In one successful embodimentthe casing 38 had a thickness of one-half inch while the face 48, Whoseouter periphery was substantially flush with the exterior of the casing,had a breadth of 1.08 inches.

A series of chisel-shaped rock-breaker teeth 50 extend below the cuttingedge 46, being spaced uniformly along the periphery of the shoe, andterminating in chisel edges 51 which extend perpendicularly to thecutting edge 46. The tooth layout is such that one tooth occupies eachcorner position, with its edge lying along a diagonal of theshoe. Thecorner teeth 52 have wider edges than the others and the spacing betweensuch corner teeth and their neighbours, as measured between the centersof chisel edges, is about the same as the spacing betwen the otherteeth. In oval or round punches, the chisel edges would be disposedalong radii from a common center.

The exterior side walls 53 of the shoe are planar, and are inclinedslightly to the longitudinal axis of the punch so that the outer ends 54of the chisel edges 51 lie outwardly of the lower marginal edges 41 ofthe casing. The inner side wall of the shoe comprises upper bevelledfaces 55 and lower bevelled faces 56, the inclination of the former tothe vertical being less than the latters. In one successful embodimentthe contained angle between faces 53 and 56 was in the range 19 to 23degrees, while the contained angle between the faces 53 and 55 was inthe range 8 to degrees.

The chisel-edge teeth and 52 narrow downwardly and are formed withbevelled side faces 57 forming a wedge 'with included apical angle ofabout 65 degree-s as measured in a vertical plane, and an included angleof about 18 degrees as measured in a horizontal plane. Theinwardly-facing fiat sides 58 of each tooth are inclined at a rake angleof about 7 degrees with respect to the longitudinal axis of the punch.The inward ends 59 of chisel edges 51 will be seen to lie inwardly ofthe inner margins 60 of the upper face of the shoe, and in a typicaldesign will be over three inches in length.

The tooth form described above has been found to provide a highlyeffective rock-breaking action when a sufiiciently energetic blow isrepeatedly directed to drive the casing and shoe downwardly throughmixed soil and rock, or through mixed fill including rock fragmentswhose cross-sectional dimensions may exceed the largest dimensions ofthe shoe. The rock-breaker teeth 50 and 52 primarily serve to shatterand/ or deflect stones encountered, while annular cutting edges 46 serveto a lesser degree to producesimilar effects while roughly shaping theinner walls 61 of vthe resulting hole. Rock fragments and earth passingupward between the side faces 57 of adjacent teeth 50 or 52 are forcedinwards by the bevelled faces and 56 of the shoe which tend to compressthe core material within the zone of constriction as the shoe descends.Matherial which passes into the chamber or space 62 above the shoewithin the casing is therefore in a somewhat worked condition but by nomeans entirely disintegrated.

The chamber 62 hasa cross-sectional area increasing abruptly immediatelyabove the aperture 42 and thereafter increases gradually and uniformlyupwards, so that the casing offers little resistance to its filling bythe core material which is in a loosened state within the chamber.Moreover, as will become more directly apparent hereinafter from adescription of the drive action, each downward increment of punchdisplacement is effected at a relatively high velocity and occurs in avery short time interval of a few microseconds. There is conquentlynegligible packing or sticking of the core to the casing.

The outer surface of the casing, which as described is preferablyslightly tapered in punches intended for setting piles or poles in rockfill, displaces the surrounding rock and earth outwards and compacts thematerial in the immediate vicinity of the hole wall 61 to provide arelatively smooth, dense surface, capable of standing without caving infor long periods of time and which does not tend to spall off and fallinto the bottom particularly during the setting of the pole or post.

In earth materials of the character glacial till or moraine depositscomprised of mixed clays, sands and fine gravels, a punch corer asdescribed will drive the shoe at a rate of as much as two to threeinches per blow; in shaly ground the punch may descend up to about oneinch per blow. River bed gravels in which the stones are rounded andaverage three inches and upward in maximum transverse dimension, havelogged rates of'drive in the range one-halfto one inch per blow. In rockfill comprised mainly of large irregular fragments with a sand or claymatrix as in highway base fill, the same punch may penetrate a fractionof an inch per blow with an irregular rate of progress depending on theconfiguration of the obstacles confronting the shoe. Such large stonesproduce astonishingly little offsetting or deflection of the punch sothat straight holes may he sunk.

On completion of a hole, the punch is raised out of the ground, and withit are lifted the contents of the hole, which are firmly held in thepunch. In almost every instance, the break boundary between the bottomof the hole and the retained core will lie in a plane roughly coincidentwith the plane of opening 47. The core material appears to be blockedagainst falling out of the shoe by the zone of compacted material Withinthe zone between apertures 42 and 47.

As the punch is driven into the ground to make a subsequent hole theretained core material from the previous hole is forced upward in thecasing and is discharged intermittently through the side opening 63surrounded by a spout 64 to deflect the issuing material laterally. Thespout comprises an upper margin formed by end wall 44, a lower curvedwall 65, casing side wall extensions 66, and a curved upper wall 67within the casing. The issuing material 68 piles up and is pushedoutwards by following material so that it accumulates relatively closeto but clear of the hole. The lower lip of the spout serves to deflectthe loose material away from the hole as the punch is lifted.

The punch is provided with a head-reinforcement 69, as by doubling ofthe casing thickness, to transmit the impact energy uniformly. Opposedapertures 76 are formed in the side walls adjacent end wall 44, toreceive hoisting means to be described hereinafter. Referringparticularly to FIGURE 6, apparatus for the holding, driving, andadjusting of the punch are shown, comprising a cap member 71 coveringthe upper end wall 44 of the casing. The cap member has an axialcylindrical recess 72 in its under side in which a boss 73 is receivedand threadedly engaged with threading 74 formed in the recess. The wall44 is apertured centrally at 76, to pass a depending integral rod-likeextension 75, which projects below wall 44. A thick pin 77 having anenlarged head 78 is re ceived in the apertures 79, and passes through anaperture 79 in the extension 75. The pin is retained engaged with thecasing and the extension by a detachable keeper fit). it will be seenthat the cap and the boss 73 may be rotated relatively to each other andto the casing, to secure the cap firmly upon the end of the casing andto take up any play or looseness due to wear.

The upper side 81 of the cap is spherically formed, having a center ofcurvature lying in the longitudinal axis of the punch at a point belowthe cap and generally in the upper half of the length of the punch. Thecap has an integral radial flange or skirt 82 of constant radialthickness, having a spherical underside 83. A support member 84surrounding the skirt comprises a thick-walled formed steel body havinan inwardly extending flange 85 bounded by a central aperture 86 of adiameter intermediate the inner and outer margins of the skirt 82, andbeing like it also of spherical shell form, so that when the skirt andflange are in contacting relation the centers of curvature of theirmeeting faces are substantially coincidentv The support member 84- has acylindrical upwardly extending portion 87 to which is secured, as byfasteners 88, a cylindrical casing 89 surrounding an anvil 90. Thelatter is captive within a casing 91, which may be a lower extension ofengine casing 33 or may be a separate casing secured detachably thereto.Anvil 90 is free to move guidedly alimited distance inside casing 91, asdetermined by a thick radial flange 92 reciprocably movable in acylindrically walled groove 93 in the casing. An inwardly projectingflange 94 extending from the upper end of casing 39 is spaced above aradial shoulder 95 of the lower portion of casing 91, and isspring-pressed by coil spring 96 to be normally out of contact with theshoulder. When the anvil casing 91 is moved upward by the actuation ofthe vertical elevators :for the box slide assembly 14, a disc 98 securedto the base of casing 91 lifts the lower end of the spring and tends tourge the casing 89 upward thereby. Because of the weight of the punchand contents, the spring will compress until shoulder 95 seats underflange 94, and further lifting of casing 91 causes flange 85 to engagethe cap 71 and to raise the punch.

may pass freely upward in space 62.

p In the setting of the punch to sink a hole, the vehicle 15 will rarelybe found to be level, so that in order to sink a vertical hole the punchmust be capable of freely swivelling in any direction. It will thereforebe understood that the provision of a spherical captive cap 71 and ofthe lifting provisions for engaging the cap with the attendantapplication of pressure distributed uniformly about the peripherythereof, makes possible the precise setting and raising of the punchregardless of theinitial attitude of the vehicle.

I Assuming now that the box slide 14 and the side columns 13 have beenoriented properly with the punch suspended to hang vertically, theelevators are operated to cause the punch to descend and to press theshoe 45 on the ground. It will be seen that the casing :91 will pressagainst the anvil flange 92, compressing impacttransfer discs 196 whichare seated in a recess 97 in the underside of the anvil, against thestriker 99. The latter has a concavely spherical under face 100corresponding to the convex curvature of impact face 81 of the punchcap. The entire weight of the percussion engine, punch support, punchand punch contents, and that of the box slide, may therefore be restedon the shoe, serving to aid in its penetration of the ground. Whateverthe form of impact means used, a piston or hammer 101 which preferablyhas a weight between 1000 and 2000 pounds or more is repeatedly causedto descend swiftly from a raised or rebound position to strike the anvil9d, and to drive the coupling and impact-transfer elements together withthe punch.

When the direction of fall of the hammer 101 is inclined to thelongitudinal axis of the punch, which usually will be vertical, thefreely swivelling contact of striker 99 and cap 71 will cause the blowto be directed into the punch axis. Provided the angle is not so greatthat the intersection of the hammer thrust line does not lie appreciablyoutside cutting edge 46, the punch may be effect'ively driven,particularly in clay, sand, and line gravel.

The inclination of the side columns as well as the lateral positioningof the box slide may be adjusted by the operator at will as the drivingoperation proceeds, to minimize the angular difference.

' Referring now to FIGURE 7, an alternative design of punch is shownhaving casing 38 formed with a double .wall, the upper end of inner wall102 meeting the casing 38 on a transverse section below the spout 64,the lower marginof the inner wall being only slightly larger than themargin of aperture 42 of the shoe in face 48. The outer wall may have azero taper, i.e., it may be straightsided with parallel walls, or, asshown, may taper slightly inwardly upwardly, while the inner Wall istapered to increase the cross-sectional area progressively upwardly toprevent packing of the core material. Such punch form is useful whereverthe compaction of the borehole 61 is unnecessary, as in certainconsolidated materials such as hard shales or clays, and in cherty sandand frozen soils.

The provision of Zero taper leaves a narrow space between the hole sidesand the casing, since the outer margin or cutting edge 46 of the shoewill be slightly greater in cross-section than any part of the casingexterior. tool form lessens the work'of driving by omitting the ,boreWall compaction, while the. loosened core material In frozen soil a shoeof the same form as shown in FIGURES 3 to 5 Such While the invention hasbeen described with particular reference to short punch casings, it isto be understood that the punch may be of considerable length permittingit to be driven to depths of as much as twenty feet or more withoutdeparting from the principles and methods described. Moreover, theapparatus may be used to excavate trenches of any configuration, bysinking a succession of closely spaced holes. The laying of utilitypipes in such trenches is feasible, by knocking out the partition wallsbetween holes at their bases, and leaving the upper portions forprotection against caving.

p I claim:

1. An earth perforating punch for sinking compacted Wall boreholes inrock fill and recovering the contents of said boreholes, comprisingan'upwardly elongate tubular casing having a closing upper end well, anopen shoe in the form of an annulus integrally joined with and dependingfrom the periphery of the lower end of said casing, said shoe having aperipheral depending cutting edge and having inner side Walls bevelledto provide an aperture of which the cross sectional area decreasesupwardly from said cutting edge, the smallest cross-sectional dimensionsof said aperture being significantly smaller than any internalcross-sectional dimensions of said casing, said shoe also having aplurality of Wedge-shaped teeth uniformly spaced apart along theperipheral cutting edge and disposed at right angles thereto, said teethhaving extension portions tapering in thickness downwardly to chiseledges depending below said cutting edge, said chisel edges having alength spanning the widest lateral dimension of said annulus andextending inwardly of the plan projection of said annulus, a sideopening in said casing adjacent said end wall, and a curved ductconnecting said opening with the interior of said casing.

2. A punch as set forth in claim 1 wherein the chisel edges form avertical included angle of about 65 degrees and said teeth have verticalshank side faces converging laterally inwardly and having a containedangle as measured in the horizontal plane of about 18 degrees.

3. A punch as set forth in claim 2 wherein said casing is thickenedadjacent said upper end wall and is apertured on opposite sides throughsaid thickened portion to receive a lifting bar therethrough, andwherein said lifting bar passes between said spout and said end Wall.

4. A punch as set forth in claim 3 wherein said casing and said shoehave a rectangular cross section, and one would be employed, differingslightly only in that the intooth is disposed in each corner of saidshoe having its chisel edge aligned with the diagonal extended to anopposite corner.

5. A punch as set forth in claim 4 wherein the tooth shanks extendupwardly outwardly from the inner ends of said chisel edges to the upperface of said shoe.

References Cited by the Examiner v UNITED STATES PATENTS 175,672 4/1876Crump -405 1,882,906 10/1932 Renter 175405 X 1,894,999 l/l933 Macready175-405 X 2,214,970 9/1940 Mooney 175405 X 2,659,584 11/1953 Dorkins94-49 X 3,194,328 7/1965 Fiore 173132 X CHARLES E. OCONNELL, Primary.Examiner.

N. C. BYERS, Assistant Examiner.

1. AN EARTH PERFORATING PUNCH FOR SINKING COMPACTED WALL BOREHOLES INROCK FILL AND RECOVERING THE CONTENTS OF SAID BOREHOLES, COMPRISING ANUPWARDLY ELONGATE TUBULAR CASING HAVING A CLOSING UPPER END WALL, ANOPEN SHOE IN THE FORM OF AN ANNULUS INTEGRALLY JOINED WITH AND DEPENDINGFROM THE PERIPHERY OF THE LOWER END OF SAID CASING, SAID SHOE HAVING APERIPHERAL DEPENDING CUTTING EDGE AND HAVING INNER SIDE WALLS BEVELLEDTO PROVIDE AN APERTURE OF WHICH THE CROSS SECTIONAL AREA DECREASESUPWARDLY FROM SAID CUTTING EDGE, THE SMALLEST CROSS-SECTIONAL DIMENSIONSOF SAID APERTURE BEING SIGNIFICANTLY SMALLER THAN ANY INTERNALCROSS-SECTIONAL DIMENSIONS OF SAID CASING, SAID SHOE ALSO HAVING APLURALITY OF WEDGE-SHAPED TEETH UNIFORMLY SPACED APART ALONG THEPERIPHERAL CUTTING